Abstracts 2004

Abstract of Publication No. 478

Annina Aebischer and Hans U. Güdel
Host sensitized near infrared to visible photon upconversion in 1% Re4+ doped Cs2NaYbBr6
J. Alloys Comp. 374, 60-62 (2004)      Full Text (PDF)      DOI-Link     

Abstract: Cs2NaYbBr6 doped with 1% Re4+ was studied by optical absorption and luminescence spectroscopy. In the cubic host lattice the Re4+ ions substitute for the octahedrally coordinated Yb3+. Visible by eye red Re4+[2T2g] upconversion (UC) luminescence centered around 14 000 cm−1 is observed upon Yb3+[2F5/2] near infrared (NIR) excitation around 10 805 cm−1 between 10 and 300 K. An energy transfer (ET) step from Yb3+[2F5/2] to Re4+[2Eg/2T1g] followed by an energy transfer upconversion (ETU) process on the Re4+ is shown to be the mechanism responsible for this phenomenon. For Yb3+ excitation at 10 805 cm−1 with a power density of 1.3 kW/cm2 the VIS/NIR emitted photon ratio is 5% at 10 K.

Last modified: 13.12.11 by Gabriela Frei